jQuery Ajax error handling, show custom exception

Question

Is there some way I can show custom exception messages as an alert in my jQuery AJAX error message?

For example, if I want to throw an exception on the server side via Struts by throw new ApplicationException("User name already exists");, I want to catch this message ('user name already exists') in the jQuery AJAX error message.

jQuery("#save").click(function () {
  if (jQuery('#form').jVal()) {
    jQuery.ajax({
      type: "POST",
      url: "saveuser.do",
      dataType: "html",
      data: "userId=" + encodeURIComponent(trim(document.forms[0].userId.value)),
      success: function (response) {
        jQuery("#usergrid").trigger("reloadGrid");
        clear();
        alert("Details saved successfully!!!");
      },
      error: function (xhr, ajaxOptions, thrownError) {
        alert(xhr.status);
        alert(thrownError);
      }
    });
  }
});

On the second alert, where I alert the thrown error, I am getting undefined and the status code is 500.

I am not sure where I am going wrong. What can I do to fix this problem?

Answer 1

 error:function (xhr, ajaxOptions, thrownError) {
        alert(xhr.status);
        alert(thrownError);
      }

in code error ajax request for catch error connect between client to server if you want show error message of your application send in success scope

such as

success: function(data){
   //   data is object  send  form server 
   //   property of data 
   //   status  type boolean 
   //   msg     type string
   //   result  type string
  if(data.status){ // true  not error 
         $('#api_text').val(data.result);
  }
  else 
  {
      $('#error_text').val(data.msg);
  }

}

Answer 2

This function basically generates unique random API key's and in case if it doesn't then pop-up dialog box with error message appears

In View Page:

<div class="form-group required">
    <label class="col-sm-2 control-label" for="input-storename"><?php echo $entry_storename; ?></label>
    <div class="col-sm-6">
        <input type="text" class="apivalue"  id="api_text" readonly name="API" value="<?php echo strtoupper(substr(md5(rand().microtime()), 0, 12)); ?>" class="form-control" />                                                                    
        <button type="button" class="changeKey1" value="Refresh">Re-Generate</button>
    </div>
</div>

<script>
$(document).ready(function(){
    $('.changeKey1').click(function(){
          debugger;
        $.ajax({
                url  :"index.php?route=account/apiaccess/regenerate",
                type :'POST',
                dataType: "json",
                async:false,
                contentType: "application/json; charset=utf-8",
                success: function(data){
                  var result =  data.sync_id.toUpperCase();
                        if(result){
                          $('#api_text').val(result);
                        }
                  debugger;
                  },
                error: function(xhr, ajaxOptions, thrownError) {
                  alert(thrownError + "\r\n" + xhr.statusText + "\r\n" + xhr.responseText);
                }

        });
    });
  });
</script>

From Controller:

public function regenerate(){
    $json = array();
    $api_key = substr(md5(rand(0,100).microtime()), 0, 12);
    $json['sync_id'] = $api_key; 
    $json['message'] = 'Successfully API Generated';
    $this->response->addHeader('Content-Type: application/json');
    $this->response->setOutput(json_encode($json));
}

The optional callback parameter specifies a callback function to run when the load() method is completed. The callback function can have different parameters:

Type: Function( jqXHR jqXHR, String textStatus, String errorThrown )

A function to be called if the request fails. The function receives three arguments: The jqXHR (in jQuery 1.4.x, XMLHttpRequest) object, a string describing the type of error that occurred and an optional exception object, if one occurred. Possible values for the second argument (besides null) are "timeout", "error", "abort", and "parsererror". When an HTTP error occurs, errorThrown receives the textual portion of the HTTP status, such as "Not Found" or "Internal Server Error." As of jQuery 1.5, the error setting can accept an array of functions. Each function will be called in turn. Note: This handler is not called for cross-domain script and cross-domain JSONP requests.